METHODS NOW USED IX FIGHTING THE GIPSY MOTH. 63 



proper food for their development, either died or spun down to the 

 ground and migrated to the deciduous growth. Owing to the sticky 

 bands on the trunks of the trees it was impossible for the caterpillars 



to again ascend to the foliage. This experiment was checked up In- 

 several other tests made by the state office, all of which showed tin- 

 same results. (See PI. IX, figs. 1, 2.) 



The practice at present in handling coniferous woodland is to cut 

 out all the deciduous growth which will furnish food for the young 

 caterpillars, and if the pines are well handed with tanglefoot early 

 in the summer, and these bands kept viscid during the caterpillar 

 season, no further treatment is necessary. These experiments have 

 resulted in the adoption of a simple and comparatively cheap method 

 of preventing the destruction of valuable coniferous woodland, and 

 as trees of this character grow satisfactorily in most sections of the 

 infested district it is possible to preserve and develop pine forests 

 at a moderate expense, regardless of the presence of the gipsy moth 

 in surrounding territory. 



The greater part of the experimental work has been along the line 

 of developing more efficient spraying methods. The use of the tower 

 on power sprayers, which will be more fully explained later in this 

 report, has resulted in a great saving in cost of treatment. In the 

 summer of 1909 several tests were made with large spraying machines 

 to determine the most effective pressures and the best size of nozzle 

 outlets. The results indicate that on the average a j-inch nozzle of 

 the type described later in this report will carry the spray 20 feet 

 farther than a j^-inch nozzle, and that it is necessary to maintain a 

 pressure of over 200 pounds in order to secure satisfactory results. 

 There are many opportunities for perfecting the present spraying 

 outfit, and much thought is being given this matter both by the 

 Bureau and state officials as well as by manufacturers who at the 

 present time are selling many spraying machines in the infested 

 region. The activity in perfecting devices will undoubtedly result 

 in better and more economical methods in the future. 



METHODS NOW USED IN FIGHTING THE GIPSY MOTH. 



Most of the methods used for destroying the gipsy moth have 

 already been mentioned, and a large number of them were in success- 

 ful use at the time the work was being carried on by the State of 

 Massachusetts during the nineties. Such methods as treating egg 

 clusters, cleaning up brush, thinning infested woodlands, and general 

 clearing-up measures have not been unproved to a great extent. The 

 use of burlap lias been continued from year to year, but owing to the 

 expense involved in applying and tending it throughout the season 

 it is not now considered as satisfactory a method as the more recent 



